11,200 mile OCI, no filter change

[Spector]

My last two OCIs with my Buick were 10,041 and 11,189, Neither one had a filter change as compared to the previous two where the filter was changed out at about 6000 miles into a 12,000 mile OCI.

Results, this last sample was the best for lowest wear metals, previous sample had a quart of oil drained out and replaced at 6000 miles, no filter change though and this one had 8 ounces drained at 6000 miles and replaced with the Brew and LC every 1000 from that point.

Comments, the previous UOA had a higher TBN which is probably due to the quart exchange at the half way point. Although this last sample had the lower TBN the wear metals, with the Brew, were the best ever for this engine with no filter change.

I also cut open this filter, nothing to the naked eye in terms of contamination. This is a vertical mount filter.

At this point I will continue with the brew added at the time of oil change, not bother to change the filter as it does not appear to have a bearing on the wear metals and see what happens. The brew may have contributed to the better results but it certainly seems that there is no adverse effect by leaving this filter in for the entire OCI.

Gives a little more evidence to my theory that in a well operating engine with a high quality oil the filter is a useless appendage for catastrophic failure only.

 

[jsharp]

I just finished up the cleaning step with Auto-Rx in my son's 215K mile Nissan that's had M1 run in for the last 150,000 miles.

I cut the filter apart today and found pretty much nothing. I even dug down into a few of the pleats to see if anything visible to the naked eye was trapped there. Still nothing. I'm going to try a magnet on it this week sometime but so far it looks like the filter caught all there was to catch. Nothing large enough to see...

 

[ex_MGB]

If find this very, very interesting. If you filter the air and fuel going into the engine, then the only other source of contamination is the engine itself.

The normal frictional wear particles are too small to be caught in the filter (do they need to be? I'll bet that part of the additive package coats those little suckers like an oyster coats a paricle of sand to make a pearl, hence, miniture ball bearings cutting friction) and if you're getting large particles past a 20k breakin period, your engine internals are self disintegrating. In that case, the filter isn't going to prolong the inevitable by much regardless.

I've a 18 hp Briggs and Stratton I/C engine which is 13 years old on my old Monkey Wards mower. No oil filter because its not a pressurized oil system, I guess. Yet, this engine doesn't use any more oil today than ever.

I'd really like to see an extended OFCI on a well maintained engine, say, 15,000 miles with oil drain and replace half way through. Then, set up a rig to get the same flow as an engine's oil pump produces and measure the pressure drop through the filter using oil with 7500 miles of engine time (you'd need an orifice plate downstream of the filter to mimic the oil system's resistance to flow). Next, do the same thing with the same oil with a new filter.

I'll bet a quart of single malt the two pressure drops are within 5% of being the same.

[ December 01, 2003, 09:06 PM: Message edited by: ex_MGB ]

 

[Gary Allan]

Hmm seems everyone wants to perform a "delta P" test on old vs. new filters. This is a hard test for most of us to perform.


Help me discount this "po-simple boy" method.

Remove old filter ..drain ..weigh

Remove 3 hour old filter ......drain.....weigh.

Wouldn't that tell you just how much dirt you've removed in a given interval??

The only thing that might be "special" is finding an accurate enough scale.

Tell me why this wouldn't work??

 

[labman]

I am afraid there are too many other variables. To start with, the filters may not all weigh the same when new. The ADBV's don't let the oil out. Old, sheared oil should drain faster than new. I have never seen much in the filters I have cut open other than the media being darker. This likely due to aa large number of particles smaller than the 20 to 40 micron particles which I definitely want filtered out. If you think of # 400 sandpaper, the abrasive is 37 microns and smaller. I think particles that size would be big enough to feel gritty even if you couldn't se them.

 

[ex_MGB]

Gotta wonder what the useful "particle capacity" in miligrams of an engine oil filter would be before its useful life was exhausted?

Given that UOA wear metals are measured in the ppm, must be around 10,000 regular oil changes at least.

Are there any examples of an oil filter so clogged with particles that it was stuck in by-pass mode and if so, how many miles were on it?

 

[Gary Allan]

quote:

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Given that UOA wear metals are measured in the ppm, must be around 10,000 regular oil changes at least.

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I kinda wonder what they use for testing procedures. When we tested our discharge to the river (a chemical dye plant) we used "Atomic Absorbtion". To test for copper you could do it two ways, TOTAL COPPER and "free copper". One you used an acid that would suspend all copper and then test it. The other ..you would just test it.

The machine used acetelene to oxidize the fluid and the machine would read what light was absorbed from the chorona of the flame ...as in what light was absent(lamp behind flame ..spectrum analizer in front of it).

In any event we wanted to always know "free copper". If by accident someone threw a pennie into the beaker (extreme example for demonstration)...it wouldn't see it. On the other hand, if they tested TOTAL COPPER with the same pennie in the beaker ....MEGA COPPER would be read.

What I'm saying is that depending on how they do it ......you could have a big chunk of piston in the sample and you could show normal wear metals.